Justin Bieber Shares Somber Selfie Following Cleveland Brawl

The 22-year-old pop star looked somber in the photo he shared late Thursday night, which did not include a caption. "Are you okay?" one commenter asked.

On Wednesday night, an eyewitness tells ET that the "Sorry" singer was knocked to the ground during an altercation in Cleveland, following a night of partying after game three of the NBA Finals. "[Bieber] was apparently talking to the girl this guy was with, and when the guy stepped in, Biebs told him he would f**k him up," the eyewitness said. "That's when fists started flying."

Hotel security took care of the incident, which can be seen in footage obtained by TMZ. Cleveland police did not respond.

The next day, Bieber posted several selfies and later deleted one of the pics that he captioned: "Not a scratch on this pretty boy."

On the next image, he wrote: "No hesitation." He later deleted that message but left the pic up on his Instagram account.

Fan video from earlier in the night shows Bieber out partying after the game. In other footage, the singer appears to walk into the hotel with the person whom he would shortly thereafter be caught fighting with on video.

A source close to Bieber told ET that his recent questionable behavior has been increasingly worrisome to his inner circle. "People around Justin are nervous about him and worry that he could have a breakdown," the source said. "He feels like people forget that he is a human being and needs privacy. Him writing those social posts about the 'no photos etc…,' that is him just being overwhelmed. It wasn't intended to make people think he is a snotty pop star, but it's definitely reflective of what he is going through right now. During his time off, he has been trying to be as normal as possible and trying to be super low-key about everything."